//	Serial.cpp - Implementation of the CSerial class
//
//	Copyright (C) 1999-2003 Ramon de Klein (Ramon.de.Klein@ict.nl)
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
// 
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


//////////////////////////////////////////////////////////////////////
// Include the standard header files

#include <crtdbg.h>
#include <tchar.h>
#include <windows.h>
#include "stdafx.h"

//////////////////////////////////////////////////////////////////////
// Include module headerfile

#include "Serial.h"


//////////////////////////////////////////////////////////////////////
// Disable warning C4127: conditional expression is constant, which
// is generated when using the _RPTF and _ASSERTE macros.

#pragma warning(disable: 4127)


//////////////////////////////////////////////////////////////////////
// Enable debug memory manager

#ifdef _DEBUG

#ifdef THIS_FILE
#undef THIS_FILE
#endif

static const char THIS_FILE[] = __FILE__;
#define new DEBUG_NEW

#endif


//////////////////////////////////////////////////////////////////////
// Helper methods

inline void CSerial::CheckRequirements (LPOVERLAPPED lpOverlapped, DWORD dwTimeout) const
{
#ifdef SERIAL_NO_OVERLAPPED

    // Check if an overlapped structure has been specified
    if (lpOverlapped || (dwTimeout != INFINITE))
    {
        // Quit application
        ::MessageBox(0,_T("Overlapped I/O and time-outs are not supported, when overlapped I/O is disabled."),_T("Serial library"), MB_ICONERROR | MB_TASKMODAL);
        ::DebugBreak();
        ::ExitProcess(0xFFFFFFF);
    }

#endif

#ifdef SERIAL_NO_CANCELIO

    // Check if 0 or INFINITE time-out has been specified, because
    // the communication I/O cannot be cancelled.
    if ((dwTimeout != 0) && (dwTimeout != INFINITE))
    {
        // Quit application
        ::MessageBox(0,_T("Timeouts are not supported, when SERIAL_NO_CANCELIO is defined"),_T("Serial library"), MB_ICONERROR | MB_TASKMODAL);
        ::DebugBreak();
        ::ExitProcess(0xFFFFFFF);
    }

#endif	// SERIAL_NO_CANCELIO

    // Avoid warnings
    (void) dwTimeout;
    (void) lpOverlapped;
}

inline BOOL CSerial::CancelCommIo (void)
{
#ifdef SERIAL_NO_CANCELIO
    // CancelIo shouldn't have been called at this point
    ::DebugBreak();
    return FALSE;
#else

    // Cancel the I/O request
    return ::CancelIo(m_hFile);

#endif	// SERIAL_NO_CANCELIO
}


//////////////////////////////////////////////////////////////////////
// Code

CSerial::CSerial ()
    : m_lLastError(ERROR_SUCCESS)
    , m_hFile(0)
    , m_eEvent(EEventNone)
    , m_dwEventMask(0)
#ifndef SERIAL_NO_OVERLAPPED
    , m_hevtOverlapped(0)
#endif
{
}

CSerial::~CSerial ()
{
    // If the device is already closed,
    // then we don't need to do anything.
    if (m_hFile)
    {
        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::~CSerial - Serial port not closed\n");

        // Close implicitly
        Close();
    }
}

CSerial::EPort CSerial::CheckPort (LPCTSTR lpszDevice)
{
    // Try to open the device
    HANDLE hFile = ::CreateFile(lpszDevice, 
                           GENERIC_READ|GENERIC_WRITE, 
                           0, 
                           0, 
                           OPEN_EXISTING, 
                           0,
                           0);

    // Check if we could open the device
    if (hFile == INVALID_HANDLE_VALUE)
    {
        // Display error
        switch (::GetLastError())
        {
        case ERROR_FILE_NOT_FOUND:
            // The specified COM-port does not exist
            return EPortNotAvailable;

        case ERROR_ACCESS_DENIED:
            // The specified COM-port is in use
            return EPortInUse;

        default:
            // Something else is wrong
            return EPortUnknownError;
        }
    }

    // Close handle
    ::CloseHandle(hFile);

    // Port is available
    return EPortAvailable;
}

LONG CSerial::Open (LPCTSTR lpszDevice, DWORD dwInQueue, DWORD dwOutQueue, bool fOverlapped)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the port isn't already opened
    if (m_hFile)
    {
        m_lLastError = ERROR_ALREADY_INITIALIZED;
        _RPTF0(_CRT_WARN,"CSerial::Open - Port already opened\n");
        return m_lLastError;
    }

    // Open the device
    m_hFile = ::CreateFile(lpszDevice,
                           GENERIC_READ|GENERIC_WRITE,
                           0,
                           0,
                           OPEN_EXISTING,
                           fOverlapped?FILE_FLAG_OVERLAPPED:0,
                           0);
    if (m_hFile == INVALID_HANDLE_VALUE)
    {
        // Reset file handle
        m_hFile = 0;

        // Display error
        m_lLastError = ::GetLastError();
        _RPTF0(_CRT_WARN, "CSerial::Open - Unable to open port\n");
        return m_lLastError;
    }

#ifndef SERIAL_NO_OVERLAPPED
    // We cannot have an event handle yet
    _ASSERTE(m_hevtOverlapped == 0);

    // Create the event handle for internal overlapped operations (manual reset)
    if (fOverlapped)
    {
        m_hevtOverlapped = ::CreateEvent(0,true,false,0);
        if (m_hevtOverlapped == 0)
        {
            // Obtain the error information
            m_lLastError = ::GetLastError();
            _RPTF0(_CRT_WARN,"CSerial::Open - Unable to create event\n");

            // Close the port
            ::CloseHandle(m_hFile);
            m_hFile = 0;

            // Return the error
            return m_lLastError;
        }
    }
#else
    
    // Overlapped flag shouldn't be specified
    _ASSERTE(!fOverlapped);

#endif

    // Setup the COM-port
    if (dwInQueue || dwOutQueue)
    {
        // Make sure the queue-sizes are reasonable sized. Win9X systems crash
        // if the input queue-size is zero. Both queues need to be at least
        // 16 bytes large.
        _ASSERTE(dwInQueue >= 16);
        _ASSERTE(dwOutQueue >= 16);

        if (!::SetupComm(m_hFile,dwInQueue,dwOutQueue))
        {
            // Display a warning
            long lLastError = ::GetLastError();
            _RPTF0(_CRT_WARN,"CSerial::Open - Unable to setup the COM-port\n");

            // Close the port
            Close();

            // Save last error from SetupComm
            m_lLastError = lLastError;
            return m_lLastError;	
        }
    }

    // Setup the default communication mask
    SetMask();

    // Non-blocking reads is default
    SetupReadTimeouts(EReadTimeoutNonblocking);

    // Setup the device for default settings
    COMMCONFIG commConfig = {0};
    DWORD dwSize = sizeof(commConfig);
    commConfig.dwSize = dwSize;
    if (::GetDefaultCommConfig(lpszDevice,&commConfig,&dwSize))
    {
        // Set the default communication configuration
        if (!::SetCommConfig(m_hFile,&commConfig,dwSize))
        {
            // Display a warning
            _RPTF0(_CRT_WARN,"CSerial::Open - Unable to set default communication configuration.\n");
        }
    }
    else
    {
        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::Open - Unable to obtain default communication configuration.\n");
    }

    // Return successful
    return m_lLastError;
}

LONG CSerial::Close (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // If the device is already closed,
    // then we don't need to do anything.
    if (m_hFile == 0)
    {
        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::Close - Method called when device is not open\n");
        return m_lLastError;
    }

#ifndef SERIAL_NO_OVERLAPPED
    // Free event handle
    if (m_hevtOverlapped)
    {
        ::CloseHandle(m_hevtOverlapped);
        m_hevtOverlapped = 0;
    }
#endif

    // Close COM port
    ::CloseHandle(m_hFile);
    m_hFile = 0;

    // Return successful
    return m_lLastError;
}

LONG CSerial::Setup (EBaudrate eBaudrate, EDataBits eDataBits, EParity eParity, EStopBits eStopBits)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::Setup - Device is not opened\n");
        return m_lLastError;
    }

    // Obtain the DCB structure for the device
    CDCB dcb;
    if (!::GetCommState(m_hFile,&dcb))
    {
        // Obtain the error code
        m_lLastError = ::	GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::Setup - Unable to obtain DCB information\n");
        return m_lLastError;
    }

    // Set the new data
    dcb.BaudRate = DWORD(eBaudrate);
    dcb.ByteSize = BYTE(eDataBits);
    dcb.Parity   = BYTE(eParity);
    dcb.StopBits = BYTE(eStopBits);

    // Determine if parity is used
    dcb.fParity  = (eParity != EParNone);

    // Set the new DCB structure
    if (!::SetCommState(m_hFile,&dcb))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::Setup - Unable to set DCB information\n");
        return m_lLastError;
    }

    // Return successful
    return m_lLastError;
}

LONG CSerial::SetEventChar (BYTE bEventChar, bool fAdjustMask)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::SetEventChar - Device is not opened\n");
        return m_lLastError;
    }

    // Obtain the DCB structure for the device
    CDCB dcb;
    if (!::GetCommState(m_hFile,&dcb))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::SetEventChar - Unable to obtain DCB information\n");
        return m_lLastError;
    }

    // Set the new event character
    dcb.EvtChar = char(bEventChar);

    // Adjust the event mask, to make sure the event will be received
    if (fAdjustMask)
    {
        // Enable 'receive event character' event.  Note that this
        // will generate an EEventNone if there is an asynchronous
        // WaitCommEvent pending.
        SetMask(GetEventMask() | EEventRcvEv);
    }

    // Set the new DCB structure
    if (!::SetCommState(m_hFile,&dcb))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::SetEventChar - Unable to set DCB information\n");
        return m_lLastError;
    }

    // Return successful
    return m_lLastError;
}

LONG CSerial::SetMask (DWORD dwEventMask)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::SetMask - Device is not opened\n");
        return m_lLastError;
    }

    // Set the new mask. Note that this will generate an EEventNone
    // if there is an asynchronous WaitCommEvent pending.
    if (!::SetCommMask(m_hFile,dwEventMask))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::SetMask - Unable to set event mask\n");
        return m_lLastError;
    }

    // Save event mask and return successful
    m_dwEventMask = dwEventMask;
    return m_lLastError;
}

LONG CSerial::WaitEvent (LPOVERLAPPED lpOverlapped, DWORD dwTimeout)
{
    // Check if time-outs are supported
    CheckRequirements(lpOverlapped,dwTimeout);

    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::WaitEvent - Device is not opened\n");
        return m_lLastError;
    }

#ifndef SERIAL_NO_OVERLAPPED

    // Check if an overlapped structure has been specified
    if (!m_hevtOverlapped && (lpOverlapped || (dwTimeout != INFINITE)))
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_FUNCTION;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::WaitEvent - Overlapped I/O is disabled, specified parameters are illegal.\n");
        return m_lLastError;
    }

    // Wait for the event to happen
    OVERLAPPED ovInternal;
    if (!lpOverlapped && m_hevtOverlapped)
    {
        // Setup our own overlapped structure
        memset(&ovInternal,0,sizeof(ovInternal));
        ovInternal.hEvent = m_hevtOverlapped;

        // Use our internal overlapped structure
        lpOverlapped = &ovInternal;
    }

    // Make sure the overlapped structure isn't busy
    _ASSERTE(!m_hevtOverlapped || HasOverlappedIoCompleted(lpOverlapped));

    // Wait for the COM event
    if (!::WaitCommEvent(m_hFile,LPDWORD(&m_eEvent),lpOverlapped))
    {
        // Set the internal error code
        long lLastError = ::GetLastError();

        // Overlapped operation in progress is not an actual error
        if (lLastError != ERROR_IO_PENDING)
        {
            // Save the error
            m_lLastError = lLastError;

            // Issue an error and quit
            _RPTF0(_CRT_WARN,"CSerial::WaitEvent - Unable to wait for COM event\n");
            return m_lLastError;
        }

        // We need to block if the client didn't specify an overlapped structure
        if (lpOverlapped == &ovInternal)
        {
            // Wait for the overlapped operation to complete
            switch (::WaitForSingleObject(lpOverlapped->hEvent,dwTimeout))
            {
            case WAIT_OBJECT_0:
                // The overlapped operation has completed
                break;

            case WAIT_TIMEOUT:
                // Cancel the I/O operation
                CancelCommIo();

                // The operation timed out. Set the internal error code and quit
                m_lLastError = ERROR_TIMEOUT;
                return m_lLastError;

            default:
                // Set the internal error code
                m_lLastError = ::GetLastError();

                // Issue an error and quit
                _RPTF0(_CRT_WARN,"CSerial::WaitEvent - Unable to wait until COM event has arrived\n");
                return m_lLastError;
            }
        }
    }
    else
    {
        // The operation completed immediatly. Just to be sure
        // we'll set the overlapped structure's event handle.
        if (lpOverlapped)
            ::SetEvent(lpOverlapped->hEvent);
    }
#else

    // Wait for the COM event
    if (!::WaitCommEvent(m_hFile,LPDWORD(&m_eEvent),0))
    {
        // Set the internal error code
        m_lLastError = ::GetLastError();

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::WaitEvent - Unable to wait for COM event\n");
        return m_lLastError;
    }

#endif

    // Return successfully
    return m_lLastError;
}


LONG CSerial::SetupHandshaking (EHandshake eHandshake)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::SetupHandshaking - Device is not opened\n");
        return m_lLastError;
    }

    // Obtain the DCB structure for the device
    CDCB dcb;
    if (!::GetCommState(m_hFile,&dcb))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::SetupHandshaking - Unable to obtain DCB information\n");
        return m_lLastError;
    }

    // Set the handshaking flags
    switch (eHandshake)
    {
    case EHandshakeOff:
        dcb.fOutxCtsFlow = false;					// Disable CTS monitoring
        dcb.fOutxDsrFlow = false;					// Disable DSR monitoring
        dcb.fDtrControl = DTR_CONTROL_DISABLE;		// Disable DTR monitoring
        dcb.fOutX = false;							// Disable XON/XOFF for transmission
        dcb.fInX = false;							// Disable XON/XOFF for receiving
        dcb.fRtsControl = RTS_CONTROL_DISABLE;		// Disable RTS (Ready To Send)
        break;

    case EHandshakeHardware:
        dcb.fOutxCtsFlow = true;					// Enable CTS monitoring
        dcb.fOutxDsrFlow = true;					// Enable DSR monitoring
        dcb.fDtrControl = DTR_CONTROL_HANDSHAKE;	// Enable DTR handshaking
        dcb.fOutX = false;							// Disable XON/XOFF for transmission
        dcb.fInX = false;							// Disable XON/XOFF for receiving
        dcb.fRtsControl = RTS_CONTROL_HANDSHAKE;	// Enable RTS handshaking
        break;

    case EHandshakeSoftware:
        dcb.fOutxCtsFlow = false;					// Disable CTS (Clear To Send)
        dcb.fOutxDsrFlow = false;					// Disable DSR (Data Set Ready)
        dcb.fDtrControl = DTR_CONTROL_DISABLE;		// Disable DTR (Data Terminal Ready)
        dcb.fOutX = true;							// Enable XON/XOFF for transmission
        dcb.fInX = true;							// Enable XON/XOFF for receiving
        dcb.fRtsControl = RTS_CONTROL_DISABLE;		// Disable RTS (Ready To Send)
        break;

    default:
        // This shouldn't be possible
        _ASSERTE(false);
        m_lLastError = E_INVALIDARG;
        return m_lLastError;
    }

    // Set the new DCB structure
    if (!::SetCommState(m_hFile,&dcb))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::SetupHandshaking - Unable to set DCB information\n");
        return m_lLastError;
    }

    // Return successful
    return m_lLastError;
}

LONG CSerial::SetupReadTimeouts (EReadTimeout eReadTimeout)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::SetupReadTimeouts - Device is not opened\n");
        return m_lLastError;
    }

    // Determine the time-outs
    COMMTIMEOUTS cto;
    if (!::GetCommTimeouts(m_hFile,&cto))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::SetupReadTimeouts - Unable to obtain timeout information\n");
        return m_lLastError;
    }

    // Set the new timeouts
    switch (eReadTimeout)
    {
    case EReadTimeoutBlocking:
        cto.ReadIntervalTimeout = 0;
        cto.ReadTotalTimeoutConstant = 0;
        cto.ReadTotalTimeoutMultiplier = 0;
        break;
    case EReadTimeoutNonblocking:
        cto.ReadIntervalTimeout = MAXDWORD;
        cto.ReadTotalTimeoutConstant = 0;
        cto.ReadTotalTimeoutMultiplier = 0;
        break;
    default:
        // This shouldn't be possible
        _ASSERTE(false);
        m_lLastError = E_INVALIDARG;
        return m_lLastError;
    }

    // Set the new DCB structure
    if (!::SetCommTimeouts(m_hFile,&cto))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::SetupReadTimeouts - Unable to set timeout information\n");
        return m_lLastError;
    }

    // Return successful
    return m_lLastError;
}

CSerial::EBaudrate CSerial::GetBaudrate (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::GetBaudrate - Device is not opened\n");
        return EBaudUnknown;
    }

    // Obtain the DCB structure for the device
    CDCB dcb;
    if (!::GetCommState(m_hFile,&dcb))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::GetBaudrate - Unable to obtain DCB information\n");
        return EBaudUnknown;
    }

    // Return the appropriate baudrate
    return EBaudrate(dcb.BaudRate);
}

CSerial::EDataBits CSerial::GetDataBits (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::GetDataBits - Device is not opened\n");
        return EDataUnknown;
    }

    // Obtain the DCB structure for the device
    CDCB dcb;
    if (!::GetCommState(m_hFile,&dcb))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::GetDataBits - Unable to obtain DCB information\n");
        return EDataUnknown;
    }

    // Return the appropriate bytesize
    return EDataBits(dcb.ByteSize);
}

CSerial::EParity CSerial::GetParity (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::GetParity - Device is not opened\n");
        return EParUnknown;
    }

    // Obtain the DCB structure for the device
    CDCB dcb;
    if (!::GetCommState(m_hFile,&dcb))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::GetParity - Unable to obtain DCB information\n");
        return EParUnknown;
    }

    // Check if parity is used
    if (!dcb.fParity)
    {
        // No parity
        return EParNone;
    }

    // Return the appropriate parity setting
    return EParity(dcb.Parity);
}

CSerial::EStopBits CSerial::GetStopBits (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::GetStopBits - Device is not opened\n");
        return EStopUnknown;
    }

    // Obtain the DCB structure for the device
    CDCB dcb;
    if (!::GetCommState(m_hFile,&dcb))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::GetStopBits - Unable to obtain DCB information\n");
        return EStopUnknown;
    }

    // Return the appropriate stopbits
    return EStopBits(dcb.StopBits);
}

DWORD CSerial::GetEventMask (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::GetEventMask - Device is not opened\n");
        return 0;
    }

    // Return the event mask
    return m_dwEventMask;
}

BYTE CSerial::GetEventChar (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::GetEventChar - Device is not opened\n");
        return 0;
    }

    // Obtain the DCB structure for the device
    CDCB dcb;
    if (!::GetCommState(m_hFile,&dcb))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::GetEventChar - Unable to obtain DCB information\n");
        return 0;
    }

    // Set the new event character
    return BYTE(dcb.EvtChar);
}

CSerial::EHandshake CSerial::GetHandshaking (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::GetHandshaking - Device is not opened\n");
        return EHandshakeUnknown;
    }

    // Obtain the DCB structure for the device
    CDCB dcb;
    if (!::GetCommState(m_hFile,&dcb))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::GetHandshaking - Unable to obtain DCB information\n");
        return EHandshakeUnknown;
    }

    // Check if hardware handshaking is being used
    if ((dcb.fDtrControl == DTR_CONTROL_HANDSHAKE) && (dcb.fRtsControl == RTS_CONTROL_HANDSHAKE))
        return EHandshakeHardware;

    // Check if software handshaking is being used
    if (dcb.fOutX && dcb.fInX)
        return EHandshakeSoftware;

    // No handshaking is being used
    return EHandshakeOff;
}

LONG CSerial::Write (const void* pData, size_t iLen, DWORD* pdwWritten, LPOVERLAPPED lpOverlapped, DWORD dwTimeout)
{
    // Check if time-outs are supported
    CheckRequirements(lpOverlapped,dwTimeout);

    // Overlapped operation should specify the pdwWritten variable
    _ASSERTE(!lpOverlapped || pdwWritten);

    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Use our own variable for read count
    DWORD dwWritten;
    if (pdwWritten == 0)
    {
        pdwWritten = &dwWritten;
    }

    // Reset the number of bytes written
    *pdwWritten = 0;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::Write - Device is not opened\n");
        return m_lLastError;
    }

#ifndef SERIAL_NO_OVERLAPPED

    // Check if an overlapped structure has been specified
    if (!m_hevtOverlapped && (lpOverlapped || (dwTimeout != INFINITE)))
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_FUNCTION;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::Write - Overlapped I/O is disabled, specified parameters are illegal.\n");
        return m_lLastError;
    }

    // Wait for the event to happen
    OVERLAPPED ovInternal;
    if (!lpOverlapped && m_hevtOverlapped)
    {
        // Setup our own overlapped structure
        memset(&ovInternal,0,sizeof(ovInternal));
        ovInternal.hEvent = m_hevtOverlapped;

        // Use our internal overlapped structure
        lpOverlapped = &ovInternal;
    }

    // Make sure the overlapped structure isn't busy
    _ASSERTE(!m_hevtOverlapped || HasOverlappedIoCompleted(lpOverlapped));

    // Write the data
    if (!::WriteFile(m_hFile,pData,iLen,pdwWritten,lpOverlapped))
    {
        // Set the internal error code
        long lLastError = ::GetLastError();

        // Overlapped operation in progress is not an actual error
        if (lLastError != ERROR_IO_PENDING)
        {
            // Save the error
            m_lLastError = lLastError;

            // Issue an error and quit
            _RPTF0(_CRT_WARN,"CSerial::Write - Unable to write the data\n");
            return m_lLastError;
        }

        // We need to block if the client didn't specify an overlapped structure
        if (lpOverlapped == &ovInternal)
        {
            // Wait for the overlapped operation to complete
            switch (::WaitForSingleObject(lpOverlapped->hEvent,dwTimeout))
            {
            case WAIT_OBJECT_0:
                // The overlapped operation has completed
                if (!::GetOverlappedResult(m_hFile,lpOverlapped,pdwWritten,FALSE))
                {
                    // Set the internal error code
                    m_lLastError = ::GetLastError();

                    _RPTF0(_CRT_WARN,"CSerial::Write - Overlapped completed without result\n");
                    return m_lLastError;
                }
                break;

            case WAIT_TIMEOUT:
                // Cancel the I/O operation
                CancelCommIo();

                // The operation timed out. Set the internal error code and quit
                m_lLastError = ERROR_TIMEOUT;
                return m_lLastError;

            default:
                // Set the internal error code
                m_lLastError = ::GetLastError();

                // Issue an error and quit
                _RPTF0(_CRT_WARN,"CSerial::Write - Unable to wait until data has been sent\n");
                return m_lLastError;
            }
        }
    }
    else
    {
        // The operation completed immediatly. Just to be sure
        // we'll set the overlapped structure's event handle.
        if (lpOverlapped)
            ::SetEvent(lpOverlapped->hEvent);
    }

#else

    // Write the data
    if (!::WriteFile(m_hFile,pData,iLen,pdwWritten,0))
    {
        // Set the internal error code
        m_lLastError = ::GetLastError();

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::Write - Unable to write the data\n");
        return m_lLastError;
    }

#endif

    // Return successfully
    return m_lLastError;
}

LONG CSerial::Write (LPCSTR pString, DWORD* pdwWritten, LPOVERLAPPED lpOverlapped, DWORD dwTimeout)
{
    // Check if time-outs are supported
    CheckRequirements(lpOverlapped,dwTimeout);

    // Determine the length of the string
    return Write(pString,strlen(pString),pdwWritten,lpOverlapped,dwTimeout);
}

LONG CSerial::Read (void* pData, size_t iLen, DWORD* pdwRead, LPOVERLAPPED lpOverlapped, DWORD dwTimeout)
{
    // Check if time-outs are supported
    CheckRequirements(lpOverlapped,dwTimeout);

    // Overlapped operation should specify the pdwRead variable
    _ASSERTE(!lpOverlapped || pdwRead);

    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Use our own variable for read count
    DWORD dwRead;
    if (pdwRead == 0)
    {
        pdwRead = &dwRead;
    }

    // Reset the number of bytes read
    *pdwRead = 0;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::Read - Device is not opened\n");
        return m_lLastError;
    }

#ifdef _DEBUG
    // The debug version fills the entire data structure with
    // 0xDC bytes, to catch buffer errors as soon as possible.
    memset(pData,0xDC,iLen);
#endif

#ifndef SERIAL_NO_OVERLAPPED

    // Check if an overlapped structure has been specified
    if (!m_hevtOverlapped && (lpOverlapped || (dwTimeout != INFINITE)))
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_FUNCTION;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::Read - Overlapped I/O is disabled, specified parameters are illegal.\n");
        return m_lLastError;
    }

    // Wait for the event to happen
    OVERLAPPED ovInternal;
    if (lpOverlapped == 0)
    {
        // Setup our own overlapped structure
        memset(&ovInternal,0,sizeof(ovInternal));
        ovInternal.hEvent = m_hevtOverlapped;

        // Use our internal overlapped structure
        lpOverlapped = &ovInternal;
    }

    // Make sure the overlapped structure isn't busy
    _ASSERTE(!m_hevtOverlapped || HasOverlappedIoCompleted(lpOverlapped));
    
    // Read the data
    if (!::ReadFile(m_hFile,pData,iLen,pdwRead,lpOverlapped))
    {
        // Set the internal error code
        long lLastError = ::GetLastError();

        // Overlapped operation in progress is not an actual error
        if (lLastError != ERROR_IO_PENDING)
        {
            // Save the error
            m_lLastError = lLastError;

            // Issue an error and quit
            _RPTF0(_CRT_WARN,"CSerial::Read - Unable to read the data\n");
            return m_lLastError;
        }

        // We need to block if the client didn't specify an overlapped structure
        if (lpOverlapped == &ovInternal)
        {
            // Wait for the overlapped operation to complete
            switch (::WaitForSingleObject(lpOverlapped->hEvent,dwTimeout))
            {
            case WAIT_OBJECT_0:
                // The overlapped operation has completed
                if (!::GetOverlappedResult(m_hFile,lpOverlapped,pdwRead,FALSE))
                {
                    // Set the internal error code
                    m_lLastError = ::GetLastError();

                    _RPTF0(_CRT_WARN,"CSerial::Read - Overlapped completed without result\n");
                    return m_lLastError;
                }
                break;

            case WAIT_TIMEOUT:
                // Cancel the I/O operation
                CancelCommIo();

                // The operation timed out. Set the internal error code and quit
                m_lLastError = ERROR_TIMEOUT;
                return m_lLastError;

            default:
                // Set the internal error code
                m_lLastError = ::GetLastError();

                // Issue an error and quit
                _RPTF0(_CRT_WARN,"CSerial::Read - Unable to wait until data has been read\n");
                return m_lLastError;
            }
        }
    }
    else
    {
        // The operation completed immediatly. Just to be sure
        // we'll set the overlapped structure's event handle.
        if (lpOverlapped)
            ::SetEvent(lpOverlapped->hEvent);
    }

#else
    
    // Read the data
    if (!::ReadFile(m_hFile,pData,iLen,pdwRead,0))
    {
        // Set the internal error code
        m_lLastError = ::GetLastError();

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::Read - Unable to read the data\n");
        return m_lLastError;
    }

#endif

    // Return successfully
    return m_lLastError;
}

LONG CSerial::Purge()
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::Purge - Device is not opened\n");
        return m_lLastError;
    }

    if (!::PurgeComm(m_hFile, PURGE_TXCLEAR | PURGE_RXCLEAR))
    {
        // Set the internal error code
        m_lLastError = ::GetLastError();
        _RPTF0(_CRT_WARN,"CSerial::Purge - Overlapped completed without result\n");
    }
    
    // Return successfully
    return m_lLastError;
}

LONG CSerial::Break (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::Break - Device is not opened\n");
        return m_lLastError;
    }

    // Set the RS-232 port in break mode for a little while
    ::SetCommBreak(m_hFile);
    ::Sleep(100);
    ::ClearCommBreak(m_hFile);

    // Return successfully
    return m_lLastError;
}

CSerial::EEvent CSerial::GetEventType (void)
{
#ifdef _DEBUG
    // Check if the event is within the mask
    if ((m_eEvent & m_dwEventMask) == 0)
        _RPTF2(_CRT_WARN,"CSerial::GetEventType - Event %08Xh not within mask %08Xh.\n", m_eEvent, m_dwEventMask);
#endif

    // Obtain the event (mask unwanted events out)
    EEvent eEvent = EEvent(m_eEvent & m_dwEventMask);

    // Reset internal event type
    m_eEvent = EEventNone;

    // Return the current cause
    return eEvent;
}

CSerial::EError CSerial::GetError (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Check if the device is open
    if (m_hFile == 0)
    {
        // Set the internal error code
        m_lLastError = ERROR_INVALID_HANDLE;

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::GetError - Device is not opened\n");
        return EErrorUnknown;
    }

    // Obtain COM status
    DWORD dwErrors = 0;
    if (!::ClearCommError(m_hFile,&dwErrors,0))
    {
        // Set the internal error code
        m_lLastError = ::GetLastError();

        // Issue an error and quit
        _RPTF0(_CRT_WARN,"CSerial::GetError - Unable to obtain COM status\n");
        return EErrorUnknown;
    }

    // Return the error
    return EError(dwErrors);
}

bool CSerial::GetCTS (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Obtain the modem status
    DWORD dwModemStat = 0;
    if (!::GetCommModemStatus(m_hFile,&dwModemStat))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::GetCTS - Unable to obtain the modem status\n");
        return false;
    }

    // Determine if CTS is on
    return (dwModemStat & MS_CTS_ON) != 0;
}

bool CSerial::GetDSR (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Obtain the modem status
    DWORD dwModemStat = 0;
    if (!::GetCommModemStatus(m_hFile,&dwModemStat))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::GetDSR - Unable to obtain the modem status\n");
        return false;
    }

    // Determine if DSR is on
    return (dwModemStat & MS_DSR_ON) != 0;
}

bool CSerial::GetRing (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Obtain the modem status
    DWORD dwModemStat = 0;
    if (!::GetCommModemStatus(m_hFile,&dwModemStat))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::GetRing - Unable to obtain the modem status");
        return false;
    }

    // Determine if Ring is on
    return (dwModemStat & MS_RING_ON) != 0;
}

bool CSerial::GetRLSD (void)
{
    // Reset error state
    m_lLastError = ERROR_SUCCESS;

    // Obtain the modem status
    DWORD dwModemStat = 0;
    if (!::GetCommModemStatus(m_hFile,&dwModemStat))
    {
        // Obtain the error code
        m_lLastError = ::GetLastError();

        // Display a warning
        _RPTF0(_CRT_WARN,"CSerial::GetRLSD - Unable to obtain the modem status");
        return false;
    }

    // Determine if RLSD is on
    return (dwModemStat & MS_RLSD_ON) != 0;
}
